Cushing's Disease in Dogs: Managing Hyperadrenocorticism

Cushing's disease (hyperadrenocorticism) is one of the most common endocrine disorders in middle-aged to older dogs, causing significant welfare impacts through its symptoms and treatment side effects.

Key Facts

Cushing's disease results from excess cortisol production, usually due to a pituitary adenoma (85-90% of cases) or adrenal tumour
Classic signs include increased thirst and urination, increased appetite, pot-bellied appearance, hair loss, and muscle weakness
Skin changes are common: thin, fragile skin, calcinosis cutis (calcium deposits), and susceptibility to infection
Certain breeds are predisposed: Poodles, Dachshunds, Boxers, Boston Terriers, and Beagles appear more frequently affected
Diagnosis requires careful testing — low-dose dexamethasone suppression test (LDDS) or ACTH stimulation test — as no single test is perfect
Medical management with trilostane or mitotane effectively controls signs in most pituitary cases
Untreated Cushing's disease predisposes dogs to diabetes, hypertension, blood clots, and severe infections

Welfare Considerations

Cushing's disease causes a broad and progressive deterioration in quality of life. Muscle weakness makes movement uncomfortable; skin fragility causes painful lesions; chronic infections are uncomfortable and distressing; and excessive thirst and urination disrupt normal routines and sleep. The pot-bellied, lethargic, hair-loss presentation is often incorrectly attributed to normal ageing, delaying diagnosis and treatment. Medical management with trilostane requires careful monitoring — both underdosing (inadequate control) and overdosing (triggering acute Addisonian crisis) carry significant welfare risks. Dogs on treatment require regular ACTH stimulation test monitoring and owners must be educated to recognise signs of over-suppression.

What You Can Do

Seek veterinary evaluation if your middle-aged or older dog develops increased thirst, urination, or a pot-bellied appearance
Request specific endocrine testing if Cushing's disease is suspected — do not assume signs are normal ageing
Ensure regular monitoring ACTH stimulation tests for dogs on trilostane or mitotane treatment
Provide comfortable bedding and easy access to outdoors for dogs with muscle weakness and increased urination
Join Cushing's support communities for owners — managing this condition benefits from shared experience
Never stop Cushing's medication abruptly without veterinary guidance — rapid withdrawal can be dangerous